Evaluation of antagonistic actinomycetes isolates as biocontrol agents against wastewater-associated bacteria

Abstract

In wastewater treatment plants the antagonistic activities of actinomycetes could be contributing significantly in microbe-removing mechanisms, which are a combination of different factors. For this purpose, out of 58 actinomycetes isolates from a wastewater treatment plant in Al-Fayoum Governorate, Egypt, only 36 different morphological isolates were selected for further studies. Although 35 isolates (97.23%) were active against one or more of tested bacteria, WD5 isolate had broad-spectrum antagonistic activity against both Gram-negative and Gram-positive tested bacteria. WD5 ethyl acetate extract recorded the highest antibacterial activity against Staphylococcus aureus MTCC 96 (23 mm) and the lowest antibacterial activity against Pseudomonas aeruginosa MTCC 2453 (11 mm). Gas chromatography-mass spectrometry analysis of extract using available NIST (National Institute of Standards and Technology) library data identified seven bioactive compounds: 2-methylbutyl acetate, 3′,5′-dinitrobenzoic acid, 1-octadecene, tetradecane, dodecane, docosane, and methylamine,N,N-bis(N.-decyl). Many earlier studies mentioned the antibacterial activity of all above seven compounds. The 16S rRNA sequence of WD5 was recorded in GenBank under the accession number MK491056 and confirmed by comparing it with the known 16S rRNA sequences in GenBank as Streptomyces sp. These results indicated antagonistic activity of actinomycetes in the removal of wastewater-associated bacteria.

Isolation, Identification, Biocontrol Activity, and Plant Growth Promoting Capability of a Superior Streptomyces tricolor Strain HM10

“…Meanwhile, Streptomyces sp. WD5 isolate from Fayoum in Egypt, had a broad-spectrum antagonistic activity against Gram-positive bacterium, Staphylococcus aureus MTCC 96 (23 mm), and Gram-negative bacterium Pseudomonas aeruginosa MTCC 2453 (11 mm), whereas Streptomyces rubrogriseus HDZ-9-47 with biofumigation improved its efficacy against Meloidogyne incognita , and reduced root galls by 41% ( Jin et al 2019 ; Salah El-Din Mohamed and Zaki 2019 ).…”

Characterization and evaluation of actinomycete from the Protaetia brevitarsis Larva Frass

“…Actinomycetes is a group of important microorganisms with ecological function function ( Salah El-Din Mohamed and Zaki, 2019 ; Elshafie and Camele, 2022 ; Elshafie et al, 2023 ) and economic value ( Chaurasia et al, 2018 ). In addition to playing major roles in organic matter cycling, actinomycetes were reported to inhibit the growth of plant pathogens in the rhizosphere ( Crits-Christoph et al, 2018 ), degrade high molecular weight compounds in polluted soils ( Shahsavari et al, 2019 ), fix nitrogen in poor soil ( Bhatti et al, 2017 ), improve the availability of nutrients for plants ( Li et al, 2020 ), and be active as plant biostimulants ( Kolton et al, 2017 ).…”

“…The capability of actinomycetes to efficiently degrade lignocellulose underscores their vital role in the carbon cycle and their potential utility in biotechnological applications aimed at biomass conversion and sustainable agriculture practices. Furthermore, approximately 70% of reported bioactive secondary metabolites are synthesized by actinomycetes, which have been widely used as insecticides, fungicides/bactericides and antitumor drugs ( Vargas Gil et al, 2009 ) and generate enormous economic value ( Salah El-Din Mohamed and Zaki, 2019 ). In previous work, we detected actinomycetes in P. brevitarsis larval frass ( Xuan et al, 2022 ); however, the characterization and evaluation of the P. brevitarsis larval frass actinomycete is still insufficient.…”